1. Field of the Invention
The field of the invention is that of amplifier devices and especially power lasers.
At present, amplification devices generally comprise an amplifier medium, an optical pumping system and a cooling device.
The pumping system is provided by power laser diodes. This mode of pumping is more efficient than optical pumping by flash lamps. At the present time, the laser diodes, which take the form of linear arrays of aligned unitary emitters, have high luminance values. As for the diodes that emit in pulsed mode, the stacking of the linear arrays provides for architectures of amplifier structures with high integration rates.
To store high light energy per unit cf volume in the amplifier media and reduce the effects induced by the thermal load, it is preferred, rather than conventional cylindrical bars, to use parallelepiped plates whose dimensions depend on the desired luminous performance characteristics.
2. Description of the Prior Art
In the prior art, light amplifier devices comprise an amplifier medium plate working with one or two incident beams, means for the pumping of the amplifier medium, the amplifier medium plate possessing two lateral faces that are parallel to each other. FIG. 1 shows a prior art configuration comprising a light beam 2, an amplifier medium 1, optical pumping means 3 and cooling means 4. The faces 01 and 02 are cut so as to be parallel and are polished so that the entry and exit of the lateral beam 2 into and from the plate occurs at the Brewster angle of incidence. The value of the tangent of the angle of incidence i is equal to the refraction index n of the medium at the wavelength of light. The angle of incidence i is linked to the refraction angle r by the following formula: i+r=.pi./2.
The length L of the plate is defined as a function of its thickness e and of the even number 2.N of rebounds made by the beam in total reflection within the medium: EQU L=2.N.e.cotan(i-r)
The pumping means 3, which are typically diodes, are usually placed on one of the main lateral faces of the plate while the cooling device 4 is placed on the other main lateral face.
In a configuration of this kind, owing to the parallel faces 01 and 02, the image of an object through the plate is seen in the same direction as the object. For many applications, this is a drawback. This is why the invention proposes to overcome this problem by proposing a high-performance amplifier device and by delivering an image inversion.